Novavax, Inc., Gaithersburg, MD, United States.
Novavax, Inc., Gaithersburg, MD, United States.
Vaccine. 2019 Sep 24;37(41):6112-6124. doi: 10.1016/j.vaccine.2019.07.089. Epub 2019 Aug 12.
Respiratory syncytial virus (RSV) is a major cause of severe respiratory disease in the very young, elderly, and immunocompromised for which there is no vaccine. The surface exposed RSV fusion (F) glycoprotein is required for membrane fusion and infection and is a desirable vaccine candidate. RSV F glycoprotein structure is dynamic and undergoes significant rearrangements during virus assembly, fusion, and infection. We have previously described an RSV fusion-inactive prefusogenic F with a mutation of one of two furin cleavage sites resulting in the p27 region on the N-terminus of F1 with a truncated fusion peptide covalently linked to F2. A processing intermediate RSV prefusogenic F has been reported in infected cells, purified F, budded virus, and elicited a strong immune response against p27 in RSV infected young children. In this report, we demonstrate that prefusogenic F, when expressed on the cell surface of Sf9 insect and human 293T cells, binds monoclonal antibodies (mAbs) that target prefusion-specific antigenic sites Ø and VIII, and mAbs targeting epitopes common to pre- and postfusion F sites II and IV. Purified prefusogenic F bound prefusion F specific mAbs to antigenic sites Ø and VIII and mAbs targeting pre- and postfusion sites II, IV, and p27. Mice immunized with prefusogenic F antigen produced significantly higher levels of anti-F IgG and RSV neutralizing antibodies than prefusion or postfusion F antigens and induced antibodies competitive with mAbs to sites Ø, VIII, II, and IV. RSV prefusogenic F neutralization antibody responses were enhanced with aluminum phosphate adjuvant and significantly higher than prefusion F. Prefusogenic F vaccine protected cotton rats against upper and lower respiratory tract infection by RSV/A. For the first time, we present the structure, antigenic profile, immunogenicity, and protective efficacy of RSV prefusogenic F nanoparticle vaccine.
呼吸道合胞病毒（RSV）是导致婴儿、老年人和免疫功能低下者发生严重呼吸道疾病的主要原因，但目前尚无针对该病毒的疫苗。RSV 表面暴露的融合（F）糖蛋白是膜融合和感染所必需的，是一种理想的疫苗候选物。RSV F 糖蛋白结构具有动态性，在病毒组装、融合和感染过程中会发生显著重排。我们之前曾描述过一种 RSV 融合失活的前融合 F 蛋白，该蛋白的一个弗林蛋白酶切割位点发生突变，导致 F1 的 N 端 p27 区域的融合肽发生截断，与 F2 发生共价连接。已在感染细胞、纯化的 F 蛋白、出芽病毒中报道了 RSV 前融合 F 的加工中间产物，并在 RSV 感染的幼儿中引发了针对 p27 的强烈免疫反应。在本报告中，我们证明了前融合 F 蛋白在 Sf9 昆虫和人 293T 细胞表面表达时，可结合针对前融合特异性抗原表位 Ø 和 VIII 的单克隆抗体（mAb），以及针对前融合和后融合 F 位点 II 和 IV 共有的表位的 mAb。纯化的前融合 F 蛋白可结合针对前融合 F 特异性抗原表位 Ø 和 VIII 的 mAb，以及针对前融合和后融合的 mAb 位点 II、IV 和 p27。用前融合 F 抗原免疫的小鼠产生的抗 F IgG 和 RSV 中和抗体水平明显高于前融合或后融合 F 抗原，并且诱导的抗体可与针对表位 Ø、VIII、II 和 IV 的 mAb 竞争。用磷酸铝佐剂增强 RSV 前融合 F 中和抗体的反应，明显高于前融合 F。前融合 F 疫苗可保护棉鼠免受 RSV/A 引起的上呼吸道和下呼吸道感染。这是首次报道 RSV 前融合 F 纳米颗粒疫苗的结构、抗原谱、免疫原性和保护效力。
